37901 Mirrlees Pioneer
When the six-cylinder Mirrlees Blackstone MB275T power unit was first lowered into carbody of the former 37150 it is unlikely that anyone involved in the re-engineering project envisioned it would still be working 38 years later, especially as the Class 38 project for which the engines were intended would be cancelled only a few months later. Built as D6850 in 1963 and already 23 years old when it was plucked from obscurity to become 37901, the doyen of the Class 37/9s, the conversion at BREL Crewe Works was completed in October 1986. Finished in Railfreight grey and quickly named Mirrlees Pioneer, like all six members of the sub class it was allocated to Cardiff Canton, who intensively diagrammed their new charges on Railfreight Metals sector services. This included doubled up on the heavy iron ore trains between Port Talbot and Llanwern, a duty previously in the hands of Class 56s. The last to gain a full repaint into the Railfreight Metal scheme in March 1991, it swapped its sub sector decals for Transrail’s big ‘T’ branding in 1995. The fun couldn’t last and it was stored unservicable by new owners EWS in November 1998 after being stopped with radiator issues a few weeks earlier. Fortunately, 37901 was acquired for preservation in September 2002 and moved to the Llangollen Railway in October 2003 where it was restored to working order. Always a popular presence at diesel galas, a sale to Colas Rail in 2016 and then Europhoenix in 2018, who quickly repainted it in their house colours prompting hopes for a speedy return to the main line. However, it wasn’t until June 2022 that it would achieve this goal, albeit flying under the flag of the EP Rail ‘spot hire’ subsidiary. Currently hired to Rail Operations Group to cover for overhauls to their existing fleet of Class 37s, 37901 was repainted back into Railfreight Metals livery in July 2024.